Stove



H. E. MILLS Dec. 3,1940.

' s'rovr:

Filed Aug. 10, 1937 2 Sheets-Sheet 1 H. E. MILLS Dec. 3, 1940.

STOVE Filed Aug. 10, 1937 2 Sheets-Sheet 2 i l l INVENTOR fiofief Z1 MZ/k. v w MORNEY i a. k

M 1 m, Q IIIIH 2 Q T 1 0.0 E WW 0 3 My Patented Dec. 3, 1940 UNITED s'r 'r s s'rovn v Herbert a. mill, Detroit, men, assignmtt Borg- Wamer corporation, a corporation of Illinois Application August 10, 1937, Serial No. "8,357 3 Claims. ((71. 128-49) Until very recently it has been customary to provide stoves with burner tops made of cast iron for supporting cooking utensils. The present tendency toward a more finished construction and more attractive styling has resulted in the use of sheet metal top construction for supporting the cooking utensils to be used on thestove.

ne of the difliculties attendant upon the use of such sheet metal parts has been an increased tendency of such parts to warp and fail to retain their shapes dueto the rather high order of heat to which they are subjected. This tendency has been accentuated by the increased use oi relatively high thermal content gases, such as natural gases, which are now being made available to customers in many large communities. and which contain in the neighborhood of one thousand B. t. u. per cubic foot. The use of socalled "bot tled gas" in communities not provided with a public gas distribution system has tended to intensity the problem, since such gases have a thermal content ranging as high as twenty-five hundred B. t. u. per cubic foot.

It has therefore become necessary to provide some means for conducting the heat away from 'burner cover partly broken away to show the the stove top parts in order to prevent their overheating and consequent warping, and to this end the present invention provides means for causing a flow of cooling air over the parts comprising the top or utensil supporting portion of the stove.

It is therefore an object of the invention to provide means for inducing a flow of cooling air over the utensil supporting structure of a stove.

An additional object is to provide instrumentalities for evenly distributing cooling air over burner parts so that such parts may be uniformly and evenly cooled.

A still further object of the invention is to utilize such air distributing means to control the amount of secondary or ambient air supplied to the gas burner.

It is also an object of the invention to reduce the size and number of parts which are exposed to the direct heat of the flame arising from the burner.

Additional objects will appear as the description proceeds and will be pointed out in connection with the appended claims. N

' To this end the invention is disclosed as residing in a stove, the top of which is composed at least in. part of members fabricated from sheet metal.

A top plate or key plate is supported in an aperture in the top panel of the stove cabinet and is provided with apertures above the burners located in a burner box, the key plate having depending therefrom from within such apertures,

a ring which cooperates with a portion of the burner to form an air metering device for the secondary burner air and which provides a flue through which cooling air and the secondary air maybe drawn.

A grate or utensil contacting member is supported at spaced points from the edgeof the key plate aperture and provides an air duct between the body of the grate and the edge or wall of the aperture in the key plate.

In order still further to reduce the amount of heat which is transmitted to the sheet metal parts of the stove top the grate is formed with only a small number of parts which project into proximity to the flame, and has very limited contact for support with the key plate at widely separated localities.

In the accompanying drawings in which similar parts are designated by similar reference characters and which are to be taken as an example of the invention and not as limiting thereof Fig. l is a perspective view of a stove with the V arrows:

Fig. 4 is a vertical sectional view taken substantially upon the plane indicated by the line 4-4 of Fig. 2 and looking in the direction of the RITOWS Fig. 5 is a sectional view through a portion of n the burner top taken substantially upon the plane indicated by the line 5-5 of Fig. 2 and looking in the direction of the arrows;

Fig. 6 is a vertical sectional view through the utensil supporting portion of the grate taken substantially upon the plane indicated by the line 6& of Fig. 5 and looking in the direction of the arrows;

Fig. 7 is a vertical sectional .view through a portion of the key plate taken substantially upon the plane indicated by the line 1-1 of Fig. 2 and looking in the direction of the arrows; and,

Fig. 8 is a vertical sectional view through a portion of the burner top parts taken substantially on the. plane indicated by the line 8-8 of Fig. 2. i

The invention is illustrated in a stove adapted for the use of so-called bottled gas wherein gas is supplied to the consumer in cylinders under a relatively high pressure and which gas, when employed in a domestic cooking range, has an extremely high thermal content per cubic foot. A stove of such a character is indicated generally at ill in Fig. 1, and comprises a cabinet l2 supported upon a base 14 and having a fiat top surface 5 which supports a burner top l8. Burner top It may be hidden by a cover 20 which is adapted to be removed by any suitable means while the stove is in use. Burner top I8 is made up of two key plates 22 shaped to fit within an aperture formed in the top surface i6 of the s'tove and supported by a flange 24 (Figs. 3 and 4) extending inwardly of said aperture slightly below the surface of the stove top l6.

Each key plate 22 is provided with apertures 26 surrounded by a downwardly bent frusto-conicalportion 26 of the key plate. From the lower edge of the frusto-conical portion 28 a series of spaced lugs 30 extend inwardly in parallel relationship to the top surface of key plate 22 and the stove top l6 to provide spaced supports for the outwa'rdly flanged upper edge 32 of a ring member 36.

A grate having a circular body portion 36 is provided with grate bars 38 which extend inwardly toward a burner 46 to provide means for supporting a cooking utensil over such burner;

The outer ends 42 of the grate bars 38 extend into thereto. The mixture flows through-the hollow point contact with the top of the key plate 22. Supplemental utensil supporting members 44 extend inwardly a short distance toward the burner 40 and are also provided with outward extensions 46 which have point contact with the key plate 22. Members 44 are arranged in pairs and are adapted to straddle raised portions 48 upon the top surface of the key plate 22 to prevent rota-- tion of the grate relative to the key plate.

Burner 40 is provided with a mixing tube 50 for supplying a combustible gas and air mixture portion 52 of the burner body into the distributing chamber 54 of a head 66 secured to the burner body by screws 58 and is discharged upwardly for combustion through a series of external ports 60 and internal ports 62. The burner 46 is provided with a flange 64 extending entirely thereabout and of diameter equal to that of the air distributing ring 34 but spaced slightly therebelow to provide an air passage 66. The flanged portion 64 of the burner is merged with the body portion thereof in a relatively long smooth curve 68.

During the operation of the burner the heat caused by combustion induces a flow of air into the space 66 between the flange 64 and ring 34. A portion of this air sweeps inwardly over the curved section 68 of the burner and about the ports 60 to provide ambient air necessary to complete the combustion of the gas issuing from the ports 60.

A further portion of this inspirated air passes upwardly within the ring 34 and flows over the grate bars 38 and 44 to cool the same. The heat arising from the burner also induces a. draft around the outside of the ring 34 causing air to flow upwardly thereabout to pass between the flange 32 of ring 34 and the key plate 22 (in the space between lugs 30) and into passage 10 between the grate body 36 and the frusto-conical portion 28 of the key plate 22. An aperture 69 is provided through the burner head 56 and t e burner body for supplying secondary air to the gas and air mixture issuing from the ports 62.

These currents of relatively cool air function to reduce the temperature of the parts in a uniform manner and to prevent such temperature from rising we point where they will be apt to warp or become distorted. Even though the parts should become relatively warm by reason of long continued use of the burner, the uniform distribution of air aiiorded by the ring member prevents uneven distribution or localizing of the heat and its consequent warpage of the parts. I

The shape of the grate bars 38 and 44 is such as to assist in the rapid dissipation of heat. It will be noted from Fig. 6 that the grate bars 38 have the cross section of an isosceles triangle having its apex disposed downwardly and its base disposed upwardly. With this construction a relatively broad flat surface is presented for supporting the cooking utensil and serves to transmit heat rapidly therethrough to the cookin utensil. The lower side of the grate bars being relatively thin, no great amount of heat will be absorbed thereby and whatever is absorbed will be rapidly transmitted through the relatively large area of the top surface to the cooking utensil.

The key plate 22 isalso provided with raised portions 12 which extend between the two burner apertures in the key plate. These raised portions 12 function as a slideway for moving cooking utensils from one burner to another and in the case of the central one, as a stop which is straddled by the supplemental grate bar ends 46.

It will be noted that this construction provides for the distribution of cool air to all of the burner top parts which are apt to become heated by exposure to the flame and that such parts will be cooled uniformly by this flow of air. With this construction, the supply of unlimited quantities of air to the burner is checked thereby requiring the burner to operate at its best efiiciency and without necessitating its heating a largevolume of inert gases. A large area of the bottom of the cooking vessel is exposed to the heat of the burner and what heat is transmitted to the grate bars is rapidly transferred through their wide flat upper surfaces to the cooking vessel.

While the invention has been described in considerable detail, it is tobe expressly understood that the description given is for the purpose of illustration only and is not definitive of the limitations of the inventive idea. The right is reserved to make such changes in the details of construction and arrangement of parts as fall within the scope of the appended claims.

I claim:

1. A stove comprising a burner box, a burner positioned in the burner box, means for supporting a cooking vessel over said burner, said means comprising a key plate having a downwardly bent frusto-conical portion defining an aperture over said burner, and a grate member supported from said key plate having an annular body portion the outer surface of which is similar to but smaller than the frusto-conical portion of said key plate, said outer surface lying adjacent to and spaced from said portion of said key plate to define a passage, and a cylindrical tube of slightly smaller diameter than the aperture defined by said frusto-conical portion of said key plate supported by and depending from said frusto-conical portion of said key plate and defining an auxiliary air passage from underneath said frustoconical portion of said key plate and communioverlying a burner, a flange extending radially. .from the lower portion of said burner, a ring depending from the edges of said key plate aperture but spaced therefrom to define a series of air ducts, said ring defining a circular air'intake port between its lower edge and the burner flange, and a grate including a ring-shaped body member positioned over said aperture and supported at spaced points from said key plate, said body member being smaller than said aperture and spaced uniformly therefrom to define an air duct therebetween in communication with the space enclosed by said ring and theports surrounding said ring.

3. A gas stove comprising a burner having a circular flange extending outwardly about its lower portion, a top plate supported above said burner and defining an upwardly opening irustoconical aperture over said burner, a flue member depending from said top plate but spaced therefrom to define air ports between the space surrounding said flue member and the upper portion of said frusto-conical aperture, said flue member extending into proximity with said burner flange to provide an air feeding slot therebetween, and a grate including a ring-shaped body member having outwardly spaced points for contacting thetop plate and supporting the grate with the body member uniformly spaced from the top plate aperture wall to define an air duct in communication with said ports and said feeding slot formed between said flue member and said flange on said burner.

- HERBERT E. MILLS. 

